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514 lines
14 KiB
C
514 lines
14 KiB
C
/* PLT trampoline. MIPS version.
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Copyright (C) 1996-2016 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Kazumoto Kojima <kkojima@info.kanagawa-u.ac.jp>.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library. If not, see
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<http://www.gnu.org/licenses/>. */
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/* FIXME: Profiling of shared libraries is not implemented yet. */
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#include <sysdep.h>
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#include <link.h>
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#include <elf.h>
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#include <ldsodefs.h>
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#include <dl-machine.h>
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#include <sysdep-cancel.h>
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/* Get link map for callers object containing STUB_PC. */
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static inline struct link_map *
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elf_machine_runtime_link_map (ElfW(Addr) gpreg, ElfW(Addr) stub_pc)
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{
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extern int _dl_mips_gnu_objects;
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/* got[1] is reserved to keep its link map address for the shared
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object generated by the gnu linker. If all are such objects, we
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can find the link map from current GPREG simply. If not so, get
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the link map for caller's object containing STUB_PC. */
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if (_dl_mips_gnu_objects)
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{
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ElfW(Addr) *got = elf_mips_got_from_gpreg (gpreg);
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ElfW(Word) g1;
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g1 = ((ElfW(Word) *) got)[1];
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if ((g1 & ELF_MIPS_GNU_GOT1_MASK) != 0)
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{
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struct link_map *l =
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(struct link_map *) (g1 & ~ELF_MIPS_GNU_GOT1_MASK);
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ElfW(Addr) base, limit;
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const ElfW(Phdr) *p = l->l_phdr;
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ElfW(Half) this, nent = l->l_phnum;
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/* For the common case of a stub being called from the containing
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object, STUB_PC will point to somewhere within the object that
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is described by the link map fetched via got[1]. Otherwise we
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have to scan all maps. */
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for (this = 0; this < nent; this++)
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{
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if (p[this].p_type == PT_LOAD)
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{
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base = p[this].p_vaddr + l->l_addr;
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limit = base + p[this].p_memsz;
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if (stub_pc >= base && stub_pc < limit)
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return l;
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}
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}
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}
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}
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struct link_map *l;
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Lmid_t nsid;
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for (nsid = 0; nsid < DL_NNS; ++nsid)
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for (l = GL(dl_ns)[nsid]._ns_loaded; l != NULL; l = l->l_next)
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{
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ElfW(Addr) base, limit;
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const ElfW(Phdr) *p = l->l_phdr;
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ElfW(Half) this, nent = l->l_phnum;
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for (this = 0; this < nent; ++this)
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{
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if (p[this].p_type == PT_LOAD)
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{
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base = p[this].p_vaddr + l->l_addr;
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limit = base + p[this].p_memsz;
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if (stub_pc >= base && stub_pc < limit)
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return l;
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}
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}
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}
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_dl_signal_error (0, NULL, NULL, "cannot find runtime link map");
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return NULL;
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}
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/* Define mips specific runtime resolver. The function __dl_runtime_resolve
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is called from assembler function _dl_runtime_resolve which converts
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special argument registers t7 ($15) and t8 ($24):
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t7 address to return to the caller of the function
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t8 index for this function symbol in .dynsym
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to usual c arguments.
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Other architectures call fixup from dl-runtime.c in
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_dl_runtime_resolve. MIPS instead calls __dl_runtime_resolve. We
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have to use our own version because of the way the got section is
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treated on MIPS (we've also got ELF_MACHINE_PLT defined). */
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/* The flag _dl_mips_gnu_objects is set if all dynamic objects are
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generated by the gnu linker. */
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int _dl_mips_gnu_objects = 1;
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/* This is called from assembly stubs below which the compiler can't see. */
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static ElfW(Addr)
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__dl_runtime_resolve (ElfW(Word), ElfW(Word), ElfW(Addr), ElfW(Addr))
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__attribute_used__;
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static ElfW(Addr)
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__dl_runtime_resolve (ElfW(Word) sym_index,
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ElfW(Word) return_address,
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ElfW(Addr) old_gpreg,
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ElfW(Addr) stub_pc)
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{
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struct link_map *l = elf_machine_runtime_link_map (old_gpreg, stub_pc);
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const ElfW(Sym) *const symtab
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= (const ElfW(Sym) *) D_PTR (l, l_info[DT_SYMTAB]);
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const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]);
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ElfW(Addr) *got
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= (ElfW(Addr) *) D_PTR (l, l_info[DT_PLTGOT]);
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const ElfW(Word) local_gotno
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= (const ElfW(Word)) l->l_info[DT_MIPS (LOCAL_GOTNO)]->d_un.d_val;
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const ElfW(Word) gotsym
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= (const ElfW(Word)) l->l_info[DT_MIPS (GOTSYM)]->d_un.d_val;
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const ElfW(Sym) *sym = &symtab[sym_index];
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struct link_map *sym_map;
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ElfW(Addr) value;
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/* FIXME: The symbol versioning stuff is not tested yet. */
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if (__builtin_expect (ELFW(ST_VISIBILITY) (sym->st_other), 0) == 0)
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{
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switch (l->l_info[VERSYMIDX (DT_VERSYM)] != NULL ? 1 : 0)
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{
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default:
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{
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const ElfW(Half) *vernum =
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(const void *) D_PTR (l, l_info[VERSYMIDX (DT_VERSYM)]);
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ElfW(Half) ndx = vernum[sym_index] & 0x7fff;
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const struct r_found_version *version = &l->l_versions[ndx];
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if (version->hash != 0)
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{
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/* We need to keep the scope around so do some locking. This is
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not necessary for objects which cannot be unloaded or when
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we are not using any threads (yet). */
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if (!RTLD_SINGLE_THREAD_P)
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THREAD_GSCOPE_SET_FLAG ();
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sym_map = _dl_lookup_symbol_x (strtab + sym->st_name, l,
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&sym, l->l_scope, version,
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ELF_RTYPE_CLASS_PLT, 0, 0);
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/* We are done with the global scope. */
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if (!RTLD_SINGLE_THREAD_P)
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THREAD_GSCOPE_RESET_FLAG ();
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break;
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}
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/* Fall through. */
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}
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case 0:
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{
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/* We need to keep the scope around so do some locking. This is
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not necessary for objects which cannot be unloaded or when
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we are not using any threads (yet). */
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int flags = DL_LOOKUP_ADD_DEPENDENCY;
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if (!RTLD_SINGLE_THREAD_P)
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{
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THREAD_GSCOPE_SET_FLAG ();
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flags |= DL_LOOKUP_GSCOPE_LOCK;
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}
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sym_map = _dl_lookup_symbol_x (strtab + sym->st_name, l, &sym,
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l->l_scope, 0, ELF_RTYPE_CLASS_PLT,
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flags, 0);
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/* We are done with the global scope. */
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if (!RTLD_SINGLE_THREAD_P)
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THREAD_GSCOPE_RESET_FLAG ();
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}
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}
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/* Currently value contains the base load address of the object
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that defines sym. Now add in the symbol offset. */
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value = (sym ? sym_map->l_addr + sym->st_value : 0);
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}
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else
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/* We already found the symbol. The module (and therefore its load
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address) is also known. */
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value = l->l_addr + sym->st_value;
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/* Apply the relocation with that value. */
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*(got + local_gotno + sym_index - gotsym) = value;
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return value;
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}
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#if _MIPS_SIM == _ABIO32
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#define ELF_DL_FRAME_SIZE 40
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#define ELF_DL_SAVE_ARG_REGS "\
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sw $15, 36($29)\n \
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sw $4, 16($29)\n \
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sw $5, 20($29)\n \
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sw $6, 24($29)\n \
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sw $7, 28($29)\n \
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"
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#define ELF_DL_RESTORE_ARG_REGS "\
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lw $31, 36($29)\n \
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lw $4, 16($29)\n \
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lw $5, 20($29)\n \
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lw $6, 24($29)\n \
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lw $7, 28($29)\n \
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"
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/* The PLT resolver should also save and restore $2 and $3, which are used
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as arguments to MIPS16 stub functions. */
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#define ELF_DL_PLT_FRAME_SIZE 48
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#define ELF_DL_PLT_SAVE_ARG_REGS \
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ELF_DL_SAVE_ARG_REGS "\
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sw $2, 40($29)\n \
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sw $3, 44($29)\n \
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"
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#define ELF_DL_PLT_RESTORE_ARG_REGS \
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ELF_DL_RESTORE_ARG_REGS "\
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lw $2, 40($29)\n \
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lw $3, 44($29)\n \
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"
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#define IFABIO32(X) X
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#define IFNEWABI(X)
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#else /* _MIPS_SIM == _ABIN32 || _MIPS_SIM == _ABI64 */
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#define ELF_DL_FRAME_SIZE 80
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#define ELF_DL_SAVE_ARG_REGS "\
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sd $15, 72($29)\n \
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sd $4, 8($29)\n \
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sd $5, 16($29)\n \
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sd $6, 24($29)\n \
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sd $7, 32($29)\n \
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sd $8, 40($29)\n \
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sd $9, 48($29)\n \
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sd $10, 56($29)\n \
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sd $11, 64($29)\n \
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"
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#define ELF_DL_RESTORE_ARG_REGS "\
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ld $31, 72($29)\n \
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ld $4, 8($29)\n \
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ld $5, 16($29)\n \
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ld $6, 24($29)\n \
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ld $7, 32($29)\n \
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ld $8, 40($29)\n \
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ld $9, 48($29)\n \
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ld $10, 56($29)\n \
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ld $11, 64($29)\n \
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"
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/* The PLT resolver should also save and restore $2 and $3, which are used
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as arguments to MIPS16 stub functions. */
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#define ELF_DL_PLT_FRAME_SIZE 96
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#define ELF_DL_PLT_SAVE_ARG_REGS \
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ELF_DL_SAVE_ARG_REGS "\
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sd $2, 80($29)\n \
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sd $3, 88($29)\n \
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"
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#define ELF_DL_PLT_RESTORE_ARG_REGS \
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ELF_DL_RESTORE_ARG_REGS "\
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ld $2, 80($29)\n \
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ld $3, 88($29)\n \
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"
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#define IFABIO32(X)
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#define IFNEWABI(X) X
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#endif
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#ifndef __mips16
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asm ("\n\
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.text\n\
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.align 2\n\
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.set nomips16\n\
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.globl _dl_runtime_resolve\n\
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.type _dl_runtime_resolve,@function\n\
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.ent _dl_runtime_resolve\n\
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_dl_runtime_resolve:\n\
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.frame $29, " STRINGXP(ELF_DL_FRAME_SIZE) ", $31\n\
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.set noreorder\n\
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# Save GP.\n\
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1: move $3, $28\n\
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# Save arguments and sp value in stack.\n\
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" STRINGXP(PTR_SUBIU) " $29, " STRINGXP(ELF_DL_FRAME_SIZE) "\n\
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# Modify t9 ($25) so as to point .cpload instruction.\n\
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" IFABIO32(STRINGXP(PTR_ADDIU) " $25, (2f-1b)\n") "\
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# Compute GP.\n\
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2: " STRINGXP(SETUP_GP) "\n\
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" STRINGXV(SETUP_GP64 (0, _dl_runtime_resolve)) "\n\
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.set reorder\n\
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# Save slot call pc.\n\
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move $2, $31\n\
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" IFABIO32(STRINGXP(CPRESTORE(32))) "\n\
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" ELF_DL_SAVE_ARG_REGS "\
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move $4, $24\n\
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move $5, $15\n\
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move $6, $3\n\
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move $7, $2\n\
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jal __dl_runtime_resolve\n\
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" ELF_DL_RESTORE_ARG_REGS "\
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" STRINGXP(RESTORE_GP64) "\n\
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" STRINGXP(PTR_ADDIU) " $29, " STRINGXP(ELF_DL_FRAME_SIZE) "\n\
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move $25, $2\n\
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jr $25\n\
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.end _dl_runtime_resolve\n\
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.previous\n\
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");
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/* Assembler veneer called from the PLT header code when using PLTs.
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Code in each PLT entry and the PLT header fills in the arguments to
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this function:
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- $15 (o32 t7, n32/n64 t3) - caller's return address
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- $24 (t8) - PLT entry index
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- $25 (t9) - address of _dl_runtime_pltresolve
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- o32 $28 (gp), n32/n64 $14 (t2) - address of .got.plt
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Different registers are used for .got.plt because the ABI was
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originally designed for o32, where gp was available (call
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clobbered). On n32/n64 gp is call saved.
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_dl_fixup needs:
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- $4 (a0) - link map address
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- $5 (a1) - .rel.plt offset (== PLT entry index * 8) */
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asm ("\n\
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.text\n\
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.align 2\n\
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.set nomips16\n\
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.globl _dl_runtime_pltresolve\n\
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.type _dl_runtime_pltresolve,@function\n\
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.ent _dl_runtime_pltresolve\n\
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_dl_runtime_pltresolve:\n\
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.frame $29, " STRINGXP(ELF_DL_PLT_FRAME_SIZE) ", $31\n\
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.set noreorder\n\
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# Save arguments and sp value in stack.\n\
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1: " STRINGXP(PTR_SUBIU) " $29, " STRINGXP(ELF_DL_PLT_FRAME_SIZE) "\n\
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" IFABIO32(STRINGXP(PTR_L) " $13, " STRINGXP(PTRSIZE) "($28)") "\n\
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" IFNEWABI(STRINGXP(PTR_L) " $13, " STRINGXP(PTRSIZE) "($14)") "\n\
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# Modify t9 ($25) so as to point .cpload instruction.\n\
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" IFABIO32(STRINGXP(PTR_ADDIU) " $25, (2f-1b)\n") "\
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# Compute GP.\n\
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2: " STRINGXP(SETUP_GP) "\n\
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" STRINGXV(SETUP_GP64 (0, _dl_runtime_pltresolve)) "\n\
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.set reorder\n\
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" IFABIO32(STRINGXP(CPRESTORE(32))) "\n\
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" ELF_DL_PLT_SAVE_ARG_REGS "\
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move $4, $13\n\
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sll $5, $24, " STRINGXP(PTRLOG) " + 1\n\
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jal _dl_fixup\n\
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move $25, $2\n\
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" ELF_DL_PLT_RESTORE_ARG_REGS "\
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" STRINGXP(RESTORE_GP64) "\n\
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" STRINGXP(PTR_ADDIU) " $29, " STRINGXP(ELF_DL_PLT_FRAME_SIZE) "\n\
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jr $25\n\
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.end _dl_runtime_pltresolve\n\
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.previous\n\
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");
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#elif _MIPS_SIM == _ABIO32 /* __mips16 */
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/* MIPS16 version, O32 only. */
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asm ("\n\
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.text\n\
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.align 2\n\
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.set mips16\n\
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.globl _dl_runtime_resolve\n\
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.type _dl_runtime_resolve,@function\n\
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.ent _dl_runtime_resolve\n\
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_dl_runtime_resolve:\n\
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.frame $29, " STRINGXP (ELF_DL_FRAME_SIZE) ", $31\n\
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# Save arguments and sp value in stack.\n\t"
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# if _MIPS_ISA >= _MIPS_ISA_MIPS32
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"save " STRINGXP (ELF_DL_FRAME_SIZE) ", $4-$7, $ra\n\t"
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# else
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"addiu $sp, -" STRINGXP (ELF_DL_FRAME_SIZE) "\n\
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sw $7, 32($sp)\n\
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sw $6, 28($sp)\n\
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sw $5, 24($sp)\n\
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sw $4, 20($sp)\n\t"
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# endif
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"# Preserve caller's $ra, for RESTORE instruction below.\n\
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move $5, $15\n\
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sw $5, 36($sp)\n\
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# Compute GP into $2.\n\
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li $2, %hi(_gp_disp)\n\
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addiu $3, $pc, %lo(_gp_disp)\n\
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sll $2, 16\n\
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addu $2, $3\n\
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lw $3, %got(__dl_runtime_resolve)($2)\n\
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move $4, $24\n\
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addiu $3, %lo(__dl_runtime_resolve)\n\
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move $7, $ra\n\
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move $6, $28\n\
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move $25, $3\n\
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jalr $3\n\t"
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# if _MIPS_ISA >= _MIPS_ISA_MIPS32
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"restore " STRINGXP(ELF_DL_FRAME_SIZE) ", $4-$7, $ra\n\t"
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# else
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"# Restore $ra, move placed further down to hide latency.\n\
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lw $4, 36($sp)\n\
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lw $5, 24($sp)\n\
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lw $6, 28($sp)\n\
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lw $7, 32($sp)\n\
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move $ra, $4\n\
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lw $4, 20($sp)\n\
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addiu $sp, " STRINGXP(ELF_DL_FRAME_SIZE) "\n\t"
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# endif
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"move $25, $2\n\
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jr $2\n\
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.end _dl_runtime_resolve\n\
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.previous\n\
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");
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asm ("\n\
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.text\n\
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.align 2\n\
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.set mips16\n\
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.globl _dl_runtime_pltresolve\n\
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.type _dl_runtime_pltresolve,@function\n\
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.ent _dl_runtime_pltresolve\n\
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_dl_runtime_pltresolve:\n\
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.frame $29, " STRINGXP(ELF_DL_PLT_FRAME_SIZE) ", $31\n\
|
|
# Save arguments and sp value in stack.\n\t"
|
|
# if _MIPS_ISA >= _MIPS_ISA_MIPS32
|
|
"save " STRINGXP(ELF_DL_PLT_FRAME_SIZE) ", $4-$7, $ra\n\t"
|
|
# else
|
|
"addiu $sp, -" STRINGXP(ELF_DL_PLT_FRAME_SIZE) "\n\
|
|
sw $7, 40($sp)\n\
|
|
sw $6, 36($sp)\n\
|
|
sw $5, 32($sp)\n\
|
|
sw $4, 28($sp)\n\t"
|
|
# endif
|
|
"# Preserve MIPS16 stub function arguments.\n\
|
|
sw $3, 20($sp)\n\
|
|
sw $2, 16($sp)\n\
|
|
# Preserve caller's $ra, for RESTORE instruction below.\n\
|
|
move $3, $15\n\
|
|
sw $3, 44($sp)\n\
|
|
# Compute GP into $2.\n\
|
|
li $2, %hi(_gp_disp)\n\
|
|
addiu $3, $pc, %lo(_gp_disp)\n\
|
|
sll $2, 16\n\
|
|
addu $2, $3\n\
|
|
# Save GP value in slot.\n\
|
|
sw $2, 24($sp)\n\
|
|
# Load _dl_fixup address.\n\
|
|
lw $6, %call16(_dl_fixup)($2)\n\
|
|
# Load link map address.\n\
|
|
move $3, $28\n\
|
|
lw $4, " STRINGXP (PTRSIZE) "($3)\n\
|
|
move $5, $24\n\
|
|
sll $5, " STRINGXP (PTRLOG) " + 1\n\
|
|
# Call _dl_fixup.\n\
|
|
move $25, $6\n\
|
|
jalr $6\n\
|
|
move $25, $2\n\
|
|
# Reload GP value into $28.\n\
|
|
lw $3, 24($sp)\n\
|
|
move $28, $3\n\
|
|
lw $3, 16($sp)\n\
|
|
move $15, $3\n\
|
|
lw $3, 20($sp)\n\t"
|
|
# if _MIPS_ISA >= _MIPS_ISA_MIPS32
|
|
"restore " STRINGXP (ELF_DL_PLT_FRAME_SIZE) ", $4-$7, $ra\n\t"
|
|
# else
|
|
"# Restore $ra, move placed further down to hide latency.\n\
|
|
lw $4, 44($sp)\n\
|
|
lw $5, 32($sp)\n\
|
|
lw $6, 36($sp)\n\
|
|
lw $7, 40($sp)\n\
|
|
move $ra, $4\n\
|
|
lw $4, 28($sp)\n\
|
|
addiu $sp, " STRINGXP (ELF_DL_PLT_FRAME_SIZE) "\n\t"
|
|
# endif
|
|
".set noreorder\n\
|
|
jr $2\n\
|
|
move $2, $15\n\
|
|
.set reorder\n\
|
|
.end _dl_runtime_pltresolve\n\
|
|
.previous\n\
|
|
");
|
|
|
|
#else /* __mips16 && _MIPS_SIM != _ABIO32 */
|
|
# error "MIPS16 support for N32/N64 not implemented"
|
|
|
|
#endif /* __mips16 */
|